Branched, scattered or verticillate; FIG.
On the other hand, the ejaculatory duct with its verticillate sac in the male of Cypris and other genera is a feature scarcely less remarkable.
29); when more than two are produced they are verticillate, and the circle of leaves is then called a verticil or whorl.
The same occurs in the verticillate arrangement, the leaves of each whorl rarely being super- posed on those of the whorl next it, but usually alterna ting so that each leaf in a whorl occupies the space be tween two leaves of the whorl next to it.
These causes of change in phyllotaxis are also well exemplified in the alteration of an opposite or verticillate arrangement to an alternate, and vice versa; thus the effect of interruption of growth, in causing alternate leaves to become opposite and verticillate, can be distinctly shown in Rhododendron ponticum.
The leaves have a definite relation to each other in the bud, being either opposite, alternate or verticillate; and thus different kinds of vernation are produced.
Such whorled or verticillate bracts generally remain separate (polyphyllous), but may be united by cohesion (gamophyllous), as in many species of Bupleurum and in Lavatera.
2 2) the pistil consists of five verticillate carpels o, alternating with the stamens e.
Carpellary leaves, and that in the progress of development these leaves separated from them, leaving the placentas and ovules free in the centre; or by supposing that the placentas are not marginal but axile formations, produced by an elongation of the axis, and the carpels verticillate leaves, united together around the axis.
The non-cellular order Siphoneae is fairly well represented in Palaeozoic strata, especially by calcareous verticillate forms referable to the family Dasycladeae; the separate tubular joints of the articulated thallus, bearing the prints of the whorled branches, are sometimes cylindrical (Arthroporella, Vermiporella, &c.), sometimes oval (Sycidium) or spherical (Cyclocrinus).
There can be no doubt that the verticillate Siphoneae, a group much isolated among recent organisms, are among the most ancient families of plants.
From the Ordovician and Silurian, however, a certain number of authentic remains of Algae (among many more that are questionable) have been investigated; they are for the most part either verticillate Siphonae, or the large - possibly Laminariaceous - Algae named Nematophycus, with the problematical but perhaps allied Pachytheca.
Many of the small female flowers borne on shoots with foliage of the Cupressus type consist of spirally disposed and not verticillate scales, e.g.